Cancer May Leave Early Warning Signs in Cheek Cells

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Smoking may bring on changes in cells that are linked with many
cancers, including breast and gynecological cancers, a new study
finds. These changes could provide an early warning sign of
cancer, particularly in cheek cells, the research showed.

Researchers analyzed cheek swabs from 790 women, and found those
who smoked were more likely to have certain changes associated
with these cancers, which people may not realize are linked with
smoking.

The researchers were looking for epigenetic
changes in cells, which are changes in the complex system of
chemicals and proteins that attach to DNA and turn genes on and
off. Such changes are associated with cancer development and can
be caused by exposure to environmental factors such as cigarette
smoke.

"Our work shows that smoking has a major impact on the epigenome
of normal cells that are directly exposed to the carcinogen,"
lead author Andrew Teschendorff, a research fellow at the
University College London (UCL) Cancer Institute,
said in a statement. "This research gets us closer to
understanding the very first steps" in cancer's development, he
said. The epigenome is network of chemical compounds around DNA
that regulates the activity of genes.

The study findings could lead to better ways to predict
people's risk of cancer, or to detect it early, Teschendorff
said.

Environmental factors, such as smoking, can disrupt a cell's
epigenome, eventually leading to the out-of-control cell growth
seen in cancer, the researchers said.

In the study, the researchers analyzed the epigenetic changes
within cells, and found a "signature" of smoking. By looking for
this signature, the researchers found they could differentiate
between normal and cancerous tissue with near absolute certainty,
including cancers in other parts of the body. [ Kick
the Habit: 10 Scientific Quit-Smoking Tips ]

The signature could also be used to predict if a pre-cancerous
lesion would progress to a full-blown invasive cancer, the
researchers said.

The ability to quickly and easily identify such changes in cells
could help doctors to predict and prevent cancers, the
researchers said.

The researchers also found that cheek cells may be a better
indicator of a woman's epigenetic changes than her blood cells.
The cheek cells showed a 40-fold increase in abnormal genetic
activities, compared with the blood samples taken from the same
people.

"These results pave the way for other studies in which easily
accessible cells can be used" to look for epigenetic changes that
may indicate a person's cancer risk, said the study's senior
author Dr. Martin Widschwendter, of UCL's Institute for Women's
Health.

"This is incredibly exciting for
women's cancers such as ovary, breast and endometrial cancer,
where predicting the cancer risk is a big challenge,"
Widschwendter said in a statement.

The researchers noted that because the study included only
samples from women, it is unclear if the findings apply to men.
Although previous epigenetic studies using blood samples have
suggested that most smoking-related changes are independent of
sex, only further research can prove if that holds true for cheek
cells as well.